Autoimmune polyglandular syndrome type 3 with multiple genetic alterations in a young male patient with type 1 diabetes mellitus

Introduction: Type 1 diabetes mellitus (T1DM) is one of the most common chronic diseases among young and adolescent patients. A genetically predisposed person develops autoantibodies against beta-cells after certain environmental stimuli. Patients with T1DM can develop other organ-specific autoantibodies, most often causing autoimmune thyroiditis, coeliac disease or pernicious anaemia. Patients with multiple autoimmune diseases might be diagnosed with one of the autoimmune polyglandular syndromes. Case presentation: We present a 32-year-old male patient with type 1 diabetes mellitus and Hashimoto-thyroiditis. The habitus and laboratory tests taken at admission led us to further investigations, tests were done to confirm pernicious anaemia, hyperhomocysteinemia and ankylosing spondylitis, as well. The latter disease raises the already higher cardiovascular risk of the diabetic patient. Conclusion: Patients with autoimmune type 1 diabetes mellitus should undergo screening for other autoimmune diseases, most importantly, autoimmune thyroid disease, pernicious anaemia and may be hyperhomocysteinaemia and primary adrenal insufficiency.